The geometry of the components making up multi-fin double-gate fin field-effect transistors (FinFETs) can lead to complications during manufacture. For example, doping of extensions in FinFETs is complicated by a shadowing affect of blocking resists when using conventional angled ion implantation. Specifically, the aspect ratio of the blocking resist thickness to fin spacing causes problems with shadowing the sides of the structure during ion implantation. This shadowing affect can lead to limited circuit density.
Conventional solutions include the use of a chevron layout of the fins with tilted implants at twist directions nearly orthogonal to the gate, and implanting end-etched fins at twist angles near orthogonal to the gate. The former conventional method is limited to chevron layout schemes, whereas the latter conventional method is dependent on fin expansion with selective silicon on very small structures, which can be very challenging.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.